Aromatic polyesters and a method for producing the same

Abstract

PCT No. PCT/JP91/01364 Sec. 371 Date Jun. 4, 1992 Sec. 102(e) Date Jun. 4, 1992 PCT Filed Oct. 7, 1991 PCT Pub. No. WO92/06129 PCT Pub. Date Apr. 16, 1992.An aromatic polyester superior in heat resistance and mechanical properties and satisfactory in lightness and color tone is provided. The aromatic polyester has resorcinol structure, has the formula (1), <IMAGE> (1) wherein R is halogen, C1-C5 alkyl, or phenyl; m is an integer of 0 to 2, and when m is 2, the two substituents represented by R may be different from each other; and gives a powder fraction having a lightness (L value) of 70 or more and a red degree (a value) of 5 or less, which powder fraction is obtained by pulverizing the heat-resistant aromatic polyester, sieving the pulverized polyester by Tyler standard sieves and being allowed to pass through 60-mesh sieve but not 325-mesh sieve.

We claim: 
     
       1. A heat-resistant aromatic polyester resin which has resorcinol structure, has the formula (1), ##STR12## and gives a powder fraction having a lightness (L value) of 80 or more and a red degree (a value) of 3 or less, which powder fraction is obtained by pulverizing the heat-resistant aromatic polyester, sieving the pulverized polyester by Tyler standard sieves and being allowed to pass through 60-mesh sieve but not 325-mesh sieve, which heat-resistant aromatic polyester resin is produced by a method which comprises polymerizing a monomer of a resorcinol diacetate produced by reacting a resorcinol having the formula (14), ##STR13## with acetic anhydride in the presence of a tertiary amine in an amount of 0.02 to 3 parts by weight per 100 parts by weight of resorcinol. 
     
     
       2. A heat-resistant aromatic polyester according to claim 1 characterized by containing at least one repeating unit selected from the group consisting of the units contained in the formula groups (2), (3) and (4), formula group (2), ##STR14## formula group (3), ##STR15## and formula group (4), ##STR16## wherein R is halogen, C 1  -C 5  alkyl, or phenyl; X is either one of ##STR17## --O--, --CH 2  --, --CH 2  --CH 2  --, ##STR18## --SO 2  -- or --S--; and m is an integer of 0 to 2, and when the number of R in the repeating units is 2 or more, the two or more substituents represented by R may be different from each other.   
     
     
       3. A heat-resistant aromatic polyester according to claim 1 characterized by comprising 40 to 80 mole % of the repeating unit of the formula (6), 29 mole % or less of the repeating unit of formula (7), 1 to 30 mole % of the repeating unit of formula (8) and 10 to mole % of the repeating unit of the formula (9), ##STR19## 
     
     
       4. A heat-resistant aromatic polyester according to claim 1 characterized by comprising 40 to 80 mole % of the repeating unit of the formula (6), 1 to 30 mole % of the repeating unit of the formula (8) and 10 to 30 mole % of t he repeating unit of the formula (9), ##STR20## 
     
     
       5. A heat-resistant aromatic polyester according to claim 1 characterized by comprising 40 to 80 mole % of the repeating unit of the formula (10), 29 mole % or less of the repeating unit of the formula (11), 1 to 30 mole % of the repeating unit of the formula (1.2) and 10 to 30 mole % of the repeating unit of the formula (13), ##STR21## wherein R is halogen, C 1  -C 5  alkyl or phenyl; m is an integer of 0 to 2, and when m is 2, the two substituents represented by R may be different from each other. 
     
     
       6. A heat-resistant aromatic polyester according to claim 1 characterized by comprising 40 to 80 mole % of the repeating unit of the formula (10), 1 to 30 mole % of the repeating unit of the formula (12) and 10 to 30 mole % of the repeating unit of the formula (13), ##STR22## 
     
     
       7. A method for producing a heat-resistant aromatic polyester which has a resorcinol structure of formula (1) ##STR23## and gives a powder fraction having a lightness (L value) of 80 or more and a red degree (a value) of 3 or less, which powder fraction is obtained by pulverizing the heat-resistant aromatic polyester, sieving the pulverized polyester by Tyler standard sieves and being allowed to pass through 60-mesh sieve but not 325-mesh sieve, which comprises polymerizing a monomer of a resorcinol diacetate produced by reacting a resorcinol having the formula (14) with acetic anhydride in the presence of a tertiary amine, ##STR24## wherein the tertiary amine is present in an amount of 0.02 to 3 pans by weight per 100 parts by weight of resorcinol. 
     
     
       8. A heat-resistant aromatic polyester resin according to claim 1, wherein the powder fraction has a red degree of 2 or less.